Is culture of nasal secretions useful in the diagnosis of acute sinusitis (sinus infection)?

Updated: Mar 01, 2018
  • Author: Itzhak Brook, MD, MSc; Chief Editor: Michael Stuart Bronze, MD  more...
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Answer

Because the nose is colonized with multiple nonpathogenic species of bacteria, care must be taken when evaluating culture results. A specific organism is considered pathogenic when more than 104 colony-forming units of the species are grown on culture or when polymorph counts are greater than 5000 cells/mL. Important to note is that this sample must be taken from the cavity of a paranasal sinus, not nasal secretions, cultures from which are considered useless. Obtaining cultures endoscopically is useful.


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